As an ophthalmologic apparatus, mainly an apparatus which acquires a tomographic image of the fundus of the subject's eye at a high resolution using an optical coherence tomography (OCT) and a scanning laser ophthalmoscope (SLO) are currently available.
Japanese Patent Application Laid-Open No. 2009-291252 discusses that an operator executes an alignment operation on the subject's eye using a joystick while observing the anterior segment of the subject's eye through a monitor and, when this alignment operation is completed, the SOL fundus image can be acquired. At this time, when the operator presses an auto-focus start switch, a focus lens arranged in an SLO optical system is moved based on the SLO fundus image. After the auto-focus lens arranged in the SLO optical system is moved, a focus lens arranged in the OCT optical system is also moved based on an SLO fundus image to execute a rough auto-focus for the OCT optical system. Further, after that, a reference mirror is moved based on the OCT tomographic image to automatically adjust a coherence gate, thereby achieving a precision auto-focus of the OCT optical system.
In addition, Japanese Patent Application Laid-Open No. 2010-181172 discusses that the operator operates a control lever to move a fundus camera unit to a subject side and then changes a display screen from an anterior segment image of the subject's eye to a fundus observation image prior to the alignment adjustment. At this time, after performing the change-over, an alignment light source is turned on to project an alignment bright point onto the subject's eye. After the alignment adjustment is completed, the focus adjustment is executed, and then, when it is determined that the alignment state is appropriate, the reference mirror is moved and the luminance value of the acquired OCT tomographic image is analyzed to automatically detect the OCT tomographic image. Japanese Patent Application Laid-Open No. 2010-181172 also discusses that the alignment adjustment may be executed manually or automatically.
When considering a physical burden on the subject, it is required to reduce a time taken until a main image capturing of the OCT is started. Because at this time, it is also desirable to reduce the burden on the operator, it is more useful to execute the alignment automatically than manually. However, when the display image is changed from the anterior segment image to the fundus observation image prior to the alignment adjustment, an alignment light source is required as well as the observation light source for acquiring the anterior segment image. Consequently, this not only leads to an enlargement in the size of the apparatus but also an increase of adjustment time due to a time taken until the alignment light source is stabilized after being turned on, thus increasing the burden on the subject.